[linux-sunxi] Re: HDMI/DVI spurious failure

[Priit Laes]

On Tue, Jan 15, 2019 at 10:49:51AM +0100, Maxime Ripard wrote:
> Hi,
> 
> (Sending those kind of bug reports to linux-sunxi doesn't really work,
> you should Cc at least the ML involved in the development of the
> driver at fault).

OK, sorry for that.

> 
> On Mon, Jan 14, 2019 at 01:29:34PM +0000, Priit Laes wrote:
> > I have a somewhat curious case with one HDMI/DVI screen that fails
> > to initialize properly every 6-7 boots. The display itself is also
> > somewhat flawed (missing HPD pin and the VSYNC/HSYNC pulse width
> > is set to 0 in EDID), but I suspect there could be some issues
> > regarding timing in A20 HDMI driver in Linux.
> > 
...

> It doesn't look related to the clock rate itself, since it doesn't
> change between the two cases. However, in one case the DDC clock is
> enabled and in the other it's disabled.
> 
> Was it taken at the same time? Maybe you can try with that patch?
> http://code.bulix.org/z7jmkm-555344?raw

Thanks, after doing ~50+ boots I haven't seen a single failure.

Previously I had following failure cases which are now both fixed:

a) Linux without u-boot HDMI, where one in every 6-7 boots failed.
b) u--boot with hdmi enabled switching to simplefb and then switching
to kms, where previously all boots ended up with garbled screen.

Priit :)
> 
> Maxime
> 
> -- 
> Maxime Ripard, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
> 
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